Placed floorstanders on 2" concrete slab - less bass (1 Viewer)

[ChrisAG]

Due to unavoidable room layout, one of my Mordaunt-Short 906 towers was partly obscured by a couch arm, which completely hid the bottom woofer and partly hid the midrange. Sound was definitely compromised because of this, though the speakers sounded good otherwise, with decent bass. They have floor spikes, and were on a carpeted floor.

In an attempt to remedy this I bought a couple of one foot square concrete patio stones and placed them under the speakers, keeping the spikes. Sound clarity improved, but now there is less bass. I think the firm connection with the floor has been lost.

The speakers have balast chambers for sand, which I have not used. Would this help? If not, are there any other things I could try to restore the bass?

 

[Paul Clarke]

In this situation I would remove the spikes. You may also experiment with replacing the support underneath from a solid square to a more open rectangle platform framing the speaker bottom. This of course would require new support material. I tried this with good effect in a similar situation.

First remove the spikes. If unsatisfactory...

Fill with sand. If unsatisactory...

Try the different support design. You can always go back to where you started. Good Luck.

 

[Hanwook_K]

Is it that the bass is gone or that it was muddy before? Sometimes what you hear as less bass is actually more acurate bass ... just being devils advocate.

 

[Robert_Dufresne]

I agree with Hanwook. Maybe less is more but I would
definitely remove the spikes. Spikes are great for
hardwood or carpetted floors but are not great on
concrete . The goal is to minimise cabinet vibration
so filling with sand should help.
Good luck
Robert

 

[MarkO]

When you raised youre speakers higher off the floor you lost some of the "floor reflection" and youre bass thined out because of it.

 

[ChrisAG]

The bass wasn't muddy before, it was nice and tight. I think the spikes on concrete did not allow a good "anchor" like the floor did. I've removed the spikes but kept the outrigger feet, and have placed thin rubber matting between the concrete and feet. I haven't cranked it up yet, but it seems to be a better platform. I'll test it this weekend.

As for the increased distance of the driver from the floor reducing the bass, that may be partly true, but I think the anchor theory above is more sound in this case (pardon the pun). I agree that filling the bottom of the speakers with sand should help also.

Thanks everyone for your input.

 

[BruZZi]

When you raised youre speakers higher off the floor you lost some of the "floor reflection" and youre bass thined out because of it.

Same thing happened to me when I put my DefTech ProTower 400 on a stand.

I lost some good bass extension doing that. But the stand height was 6" high.

 

[Frank_S]

Chris, I did a similar thing, had my N804's on top of concrete slabs but I actually spiked the slabs to the subfloor.

I did'nt like the performance with concrete so I bought some 1" thick ash and finished and stained them to match my N804's. I have the ash platforms spiked to my subfloor and my speakers spiked to the ash platforms. I have a very rigid setup and get very tight bass response now. I think wood makes a better platform than concrete.

 

[ChrisAG]

Frank,

Is "Ash" a specific wood type, and where did you buy it? Can it dry out and warp over time?